what does Carpenter ant sawdust look like? or do i have termites?

That's a lot of "saw" dust. Saaanen is right -- you can hear carpenter ants chewing. A stethoscope helps, but if it is quiet, none is needed.

I'm not familiar with carpenter bees. Termites have one distinguishing feature -- they go "home" every night, and home is underground. They can't stand light, so they create mud tunnels running to the wood they want to munch. As such, one can usually detect termites by finding the mud tunnels, often running up your outer foundation wall.

Carpenter ants will just set up shop in wet, punky (soft) wood. They can do a lot of damage, which spreads. An improperly set up deck can lead to damage to your house's sills, and spread from there. Improper flashing where the deck meets the house is often the culprit.

First, check above where the dust was found. See anything unseemly? Check for failed paint, soft wood. If nothing above, I think you may have the very unlovely task of climbing under your deck. Bring a screwdriver, so you can poke around the area underneath where you found the "saw" dust. You may want a flashlight to look for the mud tunnels. If you don't find anything down there, maybe you do have "carpenter bees", which I don't know about.

Termite Sawdust

I, fortunately, have never had termites, but I have had carpenter ants. You'd know it. You can hear the chewing.

Depends on where you live. Generally where you have one you won't have the other. I would suggest calling a pest control company that will come out and do a walk through/ estimate for free. You're not obligated and you'll have answers. That's not a normal occurrence.

if it is a whole u might have what i do bees they are carpenter bees but their homes are only like the size of a dime. i dont like them. u might want to call someone and have them come and out and just make sure i would go on ahead and get it sprayed for termites so u dont get them.